Generally, interior board materials for buildings, such as plaster or ceramic boards, are manufactured by forming plaster into a board and attaching paper to opposite sides thereof to maintain a structure capable of enduring sheer strength.
Such plaster boards have excellent insulation properties and flame retardancy but are easily slackened by moisture on coupled portions, so that the structure breaks or is easily destroyed due to low strength, for example, when a nail is hammered thereto.
That is, plaster, widely used as a board material in the art, has a density of 0.7 g/cm3, making it difficult to mix with other additives having a relatively high specific gravity, and can easily break due to its low strength. Thus, a board needs to be formed thick to have a predetermined thickness or more.
As described above, due to vulnerability to moisture and low strength, conventional plaster boards are not useful for construction materials which require high strength and water resistance.
Thus, there is an increasing need for development of a board which has appropriate properties to solve low strength and water resistance of the conventional plaster board and to be used for interior building materials.